.org{
    position: absolute;
    left: 15px;
    width: calc(20% - 15px);
    height: 100%;
    border-right: solid 1px gray;
}
.item {
    position: absolute;
    width: calc(80% - 15px);
    height: 100%;
    right: 15px;
    border-left: solid 1px gray;
}
#tree {
    position: absolute;
    top: 9px;
    right: 15px;
    width: calc(100% - 15px);
    height: calc(100% - 9px);
}

@media screen and (max-width: 1080px){
    .org {
        position: center;
        left: 15px;
        width: calc(30% - 15px);
        height: 100%;
        border-right: solid 1px gray;
    }
    .item {
        position: absolute;
        width: calc(70% - 15px);
        height: 100%;
        right: 15px;
        border-left: solid 1px gray;
    }
}